Quantum effects on in the
MSSM:
a window to "virtual'' supersymmetry?
J.A. Coarasa - David Garcia - Jaume Guasch - Ricardo A. Jiménez - Joan Solà
Grup de Física Teòrica, Institut de Física d'Altes Energies, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain
Received: 18 April 1997 / Revised version: 18 June 1997
Abstract
We analyze the one-loop effects (strong and electroweak) on the unconventional
top quark decay mode within the MSSM. The results are
presented in the on-shell renormalization scheme with a physically well
motivated definition of . The study of this process at the quantum
level is useful to unravel the potential supersymmetric nature of the charged
Higgs emerging from that decay. As compared with the standard mode
, the corrections to are
large, slowly decoupling and persist at a sizeable level even for all
sparticle masses well above the LEP 200 discovery range. As a matter of fact,
the potential size of the SUSY effects, which amount to corrections of several
ten percent, could counterbalance the standard QCD corrections and even make
them to appear with the "wrong'' sign. Therefore, if the charged Higgs decay
of the top quark is kinematically allowed - a possibility which is not
excluded by the existing measurements of the branching ratio at the Tevatron - it could be an invaluable laboratory to search
for "virtual'' supersymmetry. While a first significant test of these
effects could possibly be performed at the upgraded Tevatron, a more precise
verification would most likely be carried out in future experiments at the
LHC.
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